A substrate in which a stacked film is formed is subjected to etching processing to form recess portions such as through-holes and via holes on the substrate. A conductive material or the like is embedded into the recess portions formed as described above to connect wiring layers located on and below the stacked film to each other or to connect a conductive pattern formed in a wiring layer and an element formed on a semiconductor substrate.
In order to increase the density of elements, prepared are fine recess portions filled with the conductive material. However, in this case, the conductive material may not be fully embedded into the fine recess portions, and may form air holes (also referred to as voids) and cause disconnection in some cases. Patent Document 1 discloses a method of manufacturing a semiconductor device with high yield by fully embedding metal into recess portions on an insulating film and suppressing formation of voids and disconnection of the metal. Specifically, Patent Document 1 discloses a method in which the recess portions formed in the insulating film are irradiated with ion beams in a direction oblique to the substrate and end portions of the insulating film around upper portions of the recess portions are thereby removed by etching. As a result, corners of the end portions are smoothed, and this facilitates subsequent embedding of the metal into the recess portions.